Back rest for chair



FIG. 1 is a perspective front View of a back rest for chair;

FIG. 2 is a perspective rear View thereof;

FIG. 3 is a front View thereof;

FIG. 4 is a rear View thereof;

FIG. 5 is a top View thereof;

FIG. 6 is a bottom View thereof;

FIG. 7 is a left side View thereof; and,

FIG. 8 is a right side View thereof. 

CLAIM The ornamental design for a back rest for chair, as shown and described. 